Kenny Elkington, now that we have the Push to Lead API, does that supercede your earlier post (/blogs/marketowhisperer/2015/09/30/make-a-marketo-form-submission-in-the-background)?
Since Push Lead (like all REST APIs) requires that you build another entire other layer and implement rate-limiting and map form inputs in the same way, it surely is not a substitute in the general case.